480 research outputs found
Entwicklung und EinfĂŒhrung von Produktionssteuerungsverbesserungen fĂŒr die kundenorientierte Halbleiterfertigung
Production control in a semiconductor production facility is a very complex and timeconsuming task. Different demands regarding facility performance parameters are defined by customer and facility management. These requirements are usually opponents, and an efficient strategy is not simple to define. In semiconductor manufacturing, the available production control systems often use priorities to define the importance of each production lot. The production lots are ranked according to the defined priorities. This process is called dispatching. The priority allocation is carried out by special algorithms. In literature, a huge variety of different strategies and rules is available. For the semiconductor foundry business, there is a need for a very flexible and adaptable policy taking the facility state and the defined requirements into account. At our case the production processes are characterized by a low-volume high-mix product portfolio. This portfolio causes additional stability problems and performance lags. The unstable characteristic increases the influence of reasonable production control logic. This thesis offers a very flexible and adaptable production control policy. This policy is based on a detailed facility model with real-life production data. The data is extracted from a real high-mix low-volume semiconductor facility. The dispatching strategy combines several dispatching rules. Different requirements like line balance, throughput optimization and on-time delivery targets can be taken into account. An automated detailed facility model calculates a semi-optimal combination of the different dispatching rules under a defined objective function. The objective function includes different demands from the management and the customer. The optimization is realized by a genetic heuristic for a fast and efficient finding of a close-to-optimal solution. The strategy is evaluated with real-life production data. The analysis with the detailed facility model of this fab shows an average improvement of 5% to 8% for several facility performance parameters like cycle time per mask layer. Finally the approach is realized and applied at a typical high-mix low-volume semiconductor facility. The system realization bases on a JAVA implementation. This implementation includes common state-of-the-art technologies such as web services. The system replaces the older production control solution. Besides the dispatching algorithm, the production policy includes the possibility to skip several metrology operations under defined boundary conditions. In a real-life production process, not all metrology operations are necessary for each lot. The thesis evaluates the influence of the sampling mechanism to the production process. The solution is included into the system implementation as a framework to assign different sampling rules to different metrology operations. Evaluations show greater improvements at bottleneck situations. After the productive introduction and usage of both systems, the practical results are evaluated. The staff survey offers good acceptance and response to the system. Furthermore positive effects on the performance measures are visible. The implemented system became part of the daily tools of a real semiconductor facility.Produktionssteuerung im Bereich der kundenorientierten Halbleiterfertigung ist heutzutage eine sehr komplexe und zeitintensive Aufgabe. Verschiedene Anforderungen bezĂŒglich der Fabrikperformance werden seitens der Kunden als auch des Fabrikmanagements definiert. Diese Anforderungen stehen oftmals in Konkurrenz. Dadurch ist eine effiziente Strategie zur Kompromissfindung nicht einfach zu definieren. Heutige Halbleiterfabriken mit ihren verfĂŒgbaren Produktionssteuerungssystemen nutzen oft prioritĂ€tsbasierte Lösungen zur Definition der Wichtigkeit eines jeden Produktionsloses. Anhand dieser PrioritĂ€ten werden die Produktionslose sortiert und bearbeitet. In der Literatur existiert eine groĂe Bandbreite verschiedener Algorithmen. Im Bereich der kundenorientierten Halbleiterfertigung wird eine sehr flexible und anpassbare Strategie benötigt, die auch den aktuellen Fabrikzustand als auch die wechselnden Kundenanforderungen berĂŒcksichtigt. Dies gilt insbesondere fĂŒr den hochvariablen geringvolumigen Produktionsfall. Diese Arbeit behandelt eine flexible Strategie fĂŒr den hochvariablen Produktionsfall einer solchen ProduktionsstĂ€tte. Der Algorithmus basiert auf einem detaillierten Fabriksimulationsmodell mit RĂŒckgriff auf Realdaten. Neben synthetischen Testdaten wurde der Algorithmus auch anhand einer realen Fertigungsumgebung geprĂŒft. Verschiedene Steuerungsregeln werden hierbei sinnvoll kombiniert und gewichtet. Wechselnde Anforderungen wie Linienbalance, Durchsatz oder Liefertermintreue können adressiert und optimiert werden. Mittels einer definierten Zielfunktion erlaubt die automatische Modellgenerierung eine Optimierung anhand des aktuellen Fabrikzustandes. Die Optimierung basiert auf einen genetischen Algorithmus fĂŒr eine flexible und effiziente Lösungssuche. Die Strategie wurde mit Realdaten aus der Fertigung einer typischen hochvariablen geringvolumigen Halbleiterfertigung geprĂŒft und analysiert. Die Analyse zeigt ein Verbesserungspotential von 5% bis 8% fĂŒr die bekannten Performancekriterien wie Cycletime im Vergleich zu gewöhnlichen statischen Steuerungspolitiken. Eine prototypische Implementierung realisiert diesen Ansatz zur Nutzung in der realen Fabrikumgebung. Die Implementierung basiert auf der JAVA-Programmiersprache. Aktuelle Implementierungsmethoden erlauben den flexiblen Einsatz in der Produktionsumgebung. Neben der Fabriksteuerung wurde die Möglichkeit der Reduktion von Messoperationszeit (auch bekannt unter Sampling) unter gegebenen Randbedingungen einer hochvariablen geringvolumigen Fertigung untersucht und geprĂŒft. Oftmals ist aufgrund stabiler Prozesse in der Fertigung die Messung aller Lose an einem bestimmten Produktionsschritt nicht notwendig. Diese Arbeit untersucht den Einfluss dieses gĂ€ngigen Verfahrens aus der Massenfertigung fĂŒr die spezielle geringvolumige Produktionsumgebung. Die Analysen zeigen insbesondere in Ausnahmesituationen wie AnlagenausfĂ€llen und KapazitĂ€tsengpĂ€sse einen positiven Effekt, wĂ€hrend der Einfluss unter normalen Produktionsbedingungen aufgrund der hohen ProduktvariabilitĂ€t als gering angesehen werden kann. Nach produktiver EinfĂŒhrung in einem typischen Vertreter dieser Halbleiterfabriken zeigten sich schnell positive Effekte auf die Fabrikperformance als auch eine breite Nutzerakzeptanz. Das implementierte System wurde Bestandteil der tĂ€glichen genutzten Werkzeuglandschaft an diesem Standort
Optimizing inventory levels using financial, lifecycle and forecast variance data
Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; in conjunction with the Leaders for Manufacturing Program at MIT, 2007.Includes bibliographical references (leaves 47-48).Significant inventory write-offs have recently plagued ATI Technologies, a world leader in graphics and media processors. ATI's product-centric culture has long deterred attention from supply chain efficiency. Given that manufacturing lead time exceeds customer order lead time for its semiconductors, ATI relies heavily on their demand forecasting team to instigate supply chain activities. The PC business unit forecasting team translates market information into product-line forecast and also sets finished goods inventory levels intended to offset demand uncertainty. Today's inventory decisions are made in response to customer escalations, often ignoring financial implications. To add necessary rigor when setting these inventory levels, this thesis presents a model using wafer and unit cost, profit margin, product lifecycle stage and historical forecast error to categorize products into inventory risk levels. The resultant risk levels become a critical input to monthly demand-supply meetings with marketing, operations and senior executives - the outcome of which are wafer orders and assembly and test plans at the world's largest contract foundries and subcontractors. Finally, the 2006 acquisition of ATI by Advanced Micro Devices (AMD) offers unforeseen flexibility, scale and challenges to the outsourced semiconductor supply chain.by Irene S. Hwang.S.M.M.B.A
On the Interaction of the PKS B1358-113 Radio Galaxy with the Abell 1836 Cluster
[abridged] Here we present the analysis of multifrequency data gathered for
the FRII radio galaxy PKS B1358-113, hosted in the brightest cluster galaxy of
Abell 1836. The galaxy harbors one of the most massive black holes known to
date and our analysis of the optical data reveals that this black hole is only
weakly active. Based on new Chandra and XMM-Newton X-ray observations and
archival radio data we derive the preferred range for the jet kinetic
luminosity erg s. This is above the values
implied by various scaling relations proposed for radio sources in galaxy
clusters, being instead very close to the maximum jet power allowed for the
given accretion rate. We constrain the radio source lifetime as
Myrs, and the total amount of deposited jet energy \,ergs. The detailed analysis of the X-ray data provides indication for
the presence of a bow-shock driven by the expanding radio lobes into the Abell
1836 cluster environment, with the corresponding Mach number . This,
together with the recently growing evidence that powerful FRII radio galaxies
may not be uncommon in the centers of clusters at higher redshifts, supports
the idea that jet-induced shock heating may indeed play an important role in
shaping the properties of clusters, galaxy groups, and galaxies in formation.
We speculate on a possible bias against detecting jet-driven shocks in poorer
environments, resulting from an inefficient electron heating at the shock
front, combined with a relatively long electron-ion equilibration timescale.Comment: Version accepted to Ap
Dynamic Multi-Product Multi-Facility Supply Network Design
Volatile MĂ€rkte, sich verkĂŒrzende Produktlebenszyklen und der globale Wettbewerb stellen die klassischen Lieferketten vor groĂe Herausforderungen.
Supply Chains mĂŒssen sich kurzfristig und dynamisch an die volatilen Marktanforderungen anpassen. Die volatilen MĂ€rkte werden immer weniger vorhersehbar. Die Supply Chains selbst mĂŒssen dynamischer werden, um die MarktvolatilitĂ€t zu bewĂ€ltigen. Daher wandelt sich das klassische Bild der stabilen Supply Chain in ein dynamisches Supply Network-VerstĂ€ndnis.
Um diese neuen Anforderungen abzudecken, schlĂ€gt diese Arbeit das Dynamic Supply Network Design Problem (DSNDP) als zentrales Instrument in hierarchischen Planungssystemen vor. Zentrales Ziel der Arbeit ist es, einen Ansatz fĂŒr das Design dynamischer Supply Networks unter gegebenen physischen Randbedingungen bereitzustellen. Um dieses Ziel zu erreichen, wird das Problem zunĂ€chst motiviert, charakterisiert und in Beziehung zum Stand der Technik der Supply Chain PlanungsansĂ€tze gesetzt. Nachdem diese Grundlage geschaffen ist, wird das Problem formalisiert.
Dazu werden alle Modellierungsannahmen formuliert. Auf dieser Grundlage werden drei aufeinander aufbauende Optimierungsmodelle fĂŒr das DSNDP entwickelt, wobei ein Mixed Integer Linear Programming (MILP) Ansatz verwendet wird. Die Optimierungsmodelle entwerfen ein dynamisches Supply Network durch die Entwicklung eines Qualifizierungsplans fĂŒr alle verfĂŒgbaren Ressourcen in jeder Periode des Planungshorizonts.
Dieses dynamische Supply Network weist den verfĂŒgbaren kapazitiven Ressourcen die entsprechenden Qualifikationen zu, um die volatile Nachfrage dynamisch zu bedienen und die Gesamtkosten zu minimieren. Dabei werden der tatsĂ€chliche Produktionsschwerpunkt jedes Produktionspartners (Produktmix-AbhĂ€ngigkeit), die spezifischen Erfahrungen jedes
Produktionspartners (Qualifizierungsabstufung), die FĂ€higkeit der Fabriken, ein Produktportfolio und nicht nur einzelne Produkte abzudecken (multitasking facility) sowie die Möglichkeit der Pre-Prozessierung berĂŒcksichtigt.
Jedes Modell wird um eine dieser Hauptannahmen erweitert. Dies macht die Modelle immer realistischer jedoch auch komplexer. EinschrĂ€nkungen in der ProblemgröĂe motivieren die Arbeit zu einem zusĂ€tzlichen heuristischen Ansatz. Die vorgeschlagene Displacement Heuristik berĂŒcksichtigt die gleichen Annahmen, löst das Designproblem jedoch iterativ.
Dadurch erreicht sie zwar niedrige Berechnungszeiten, verliert aber die OptimalitĂ€tsgarantie. Durch die geringen Rechenzeiten ist die Heuristik fĂŒr realistische industrielle Problemstellungen geeignet. Die Displacement Heuristik fĂŒhrt zu OptimalitĂ€tslĂŒcken von 4 bis 6%, wie die Validierung gegen das Optimierungsmodell zeigt. Mit spezifischen Experimenten wird das Verhalten der Displacement-Heuristik in realistischen industriellen Problemstellungen evaluiert. Aus den Erkenntnissen dieser Auswertung lassen sich mehrere konkrete VorschlĂ€ge fĂŒr die Gestaltung und das Management dynamischer Supply Networks ableiten. Da der Trend zu VolatilitĂ€t und kĂŒrzeren Produktlebenszyklen anhĂ€lt, ist zum Abschluss dieser Arbeit eine Motivation fĂŒr weitere Forschungs- und UmsetzungsaktivitĂ€ten auf dem Gebiet der dynamischen Wertschöpfungsnetzgestaltung gegeben
Co-Package Technology Platform for Low-Power and Low-Cost Data Centers
We report recent advances in photonicâelectronic integration developed in the European research project L3MATRIX. The aim of the project was to demonstrate the basic building blocks of a co-packaged optical system. Two-dimensional silicon photonics arrays with 64 modulators were fabricated. Novel modulation schemes based on slow light modulation were developed to assist in achieving an efficient performance of the module. Integration of DFB laser sources within each cell in the matrix was demonstrated as well using wafer bonding between the InP and SOI wafers. Improved semiconductor quantum dot MBE growth, characterization and gain stack designs were developed. Packaging of these 2D photonic arrays in a chiplet configuration was demonstrated using a vertical integration approach in which the optical interconnect matrix was flip-chip assembled on top of a CMOS mimic chip with 2D vertical fiber coupling. The optical chiplet was further assembled on a substrate to facilitate integration with the multi-chip module of the co-packaged system with a switch surrounded by several such optical chiplets. We summarize the features of the L3MATRIX co-package technology platform and its holistic toolbox of technologies to address the next generation of computing challenges
Recommended from our members
The adoption of Application Specific Integrated Circuit (ASIC) technology by the UK manufacturing base
Since the late 1970s, families of microelectronic technologies that could bring the advantages of high levels of electronic integration have been available at reasonable prices and manageable risk to all sectors of UK industry. However, the uptake of these technologies has been painfully slow, particularly by the small and medium enterprises (SMEs) that make up most of the companies currently operating in the UK. It is the aim of the research described here to assess how slow the uptake has been, the reasons for it, and possible solutions to the problem. The problem is investigated with reference to SMEs.
In order to reach conclusions it has been necessary to:-
âą Define Application Specific Integrated Circuit (ASIC) technology and review its history
âą Review that nature of the UK SME base and identify why they should use ASICs
âą Review the UK, European and World ASIC markets
âą Analyse the nature of the UK ASIC design and supply industry
âą Ascertain the reasons for non-adoption and assess their validity
âą Relate the findings of this research to appropriate business, organisational and system models
âą Review past and existing technology-transfer programmes operating in the area of ASIC adoption at a UK, European and world level
âą Compare the adoption of ASIC technology with the adoption of similar, wide-ranging, new technologies
The study concludes that the technology is unique in the wide range of industries to which it can be applied, and that although some advances in adoption have been made, there remains a significant number of hurdles to adoption which can best be addressed by government intervention and supporting activity from supply-companies, trade associations, user-groups and professional and educational institutions. Only once adoption has reached a 'critical mass' can it be assumed that a self-sustaining market will result
An Opportunity Assessment for a New Business Model in the Semiconductor Industry
The report presents an opportunity assessment for the business model of the Semiconductor Consulting Services Provider (SCSP) within the semiconductor industry. This assessment justifies the business needs for this model by examining the evolution of the semiconductor industry to date. The value proposition of this model is discussed based on its cost advantages relative to existing operating models within the industry. The two dominant operating models in the semiconductor industry, namely, Integrated Device Manufacturer (IDM) and Fabless Semiconductor Manufacturer (FSM), are presented. The relevance and appeal of the SCSP business model to IDM and FSM is discussed. Industry experts further provided their input in this study regarding the attractiveness of the SCSP model to fill the gap in the semiconductor industry. This report concludes that SCSP is a viable business model and that the SCSP market will grow in revenue. As a new entrant, SCSP companies should begin by strategically focusing on FSM startupsâ manufacturing and operations outsourcing, followed by existing FSM companies and finally IDM companies
A Proposal for a Three Detector Short-Baseline Neutrino Oscillation Program in the Fermilab Booster Neutrino Beam
A Short-Baseline Neutrino (SBN) physics program of three LAr-TPC detectors
located along the Booster Neutrino Beam (BNB) at Fermilab is presented. This
new SBN Program will deliver a rich and compelling physics opportunity,
including the ability to resolve a class of experimental anomalies in neutrino
physics and to perform the most sensitive search to date for sterile neutrinos
at the eV mass-scale through both appearance and disappearance oscillation
channels. Using data sets of 6.6e20 protons on target (P.O.T.) in the LAr1-ND
and ICARUS T600 detectors plus 13.2e20 P.O.T. in the MicroBooNE detector, we
estimate that a search for muon neutrino to electron neutrino appearance can be
performed with ~5 sigma sensitivity for the LSND allowed (99% C.L.) parameter
region. In this proposal for the SBN Program, we describe the physics analysis,
the conceptual design of the LAr1-ND detector, the design and refurbishment of
the T600 detector, the necessary infrastructure required to execute the
program, and a possible reconfiguration of the BNB target and horn system to
improve its performance for oscillation searches.Comment: 209 pages, 129 figure
- âŠ